Process for reclaiming vulcanized-rubber waste.



ADOLF KITTEL; OF VIENNA, AUSTRIA-HUNGARY.

PROCESS FOR REQLAIMING VULQANlZED-RUBBER WASTE.

7 Specification of Letters Patent.

Patented Jul 3, 1906;

Application filed September 2 3, 1903. Serial No. 174,252.

To all whom if may concern;

Be it known that I, ADOLF KITTEL, a subject of the Emperor of Austria-Hungary, and

a resident of Vienna, Austria-Hun ary,'have invented a certain new and useful rocess for Reclaiming Vulcanized- Rubber Waste, of which the ollowing is a specification.

This invention is a process of reclaiming vulcanized-rubber waste; and it has for its obj ect to so treat the waste material that it can be utilized in the shortest time possible, it be.- ing of more importance, considering the uses to which the product is intended to be put, to perform the process expeditiously than wit? perfect thoroughness.

I am aware that it is not broadly new to mix an alkali with vulcanized-rubber waste with the purpose of devulcanizing the rubber; but a substantial difference between the processes heretofore known and the present one resides in the fact that none of the known processes involves a compression of a mixture containing the vulcanized-rubber waste and a suitable sulfur-absorbing alkali before submitting the mass ,to the action of heat. A further substantial difference resides in the fact that my process is distinctively, from beginning to' end, a dry process, even the temperature to which the heating of the mixture is carried being not so high as to causethe mixture to melt or liquefy.

By way of exemplification I will now de scribe the preferred manner of carrying out my method.

The vulcanized-rubber-waste after having been mixed in a dry state with a sulfur-absorbing and powdered alkali is pressed into' cakes in a suitable press, and such cakes are then submitted to a temperature of from 220to 280 centigrade for two or three hours, according tothe class of rubber being devulcanized or regenerated.

The mechanical Work exerted while the mixture is being compressed into cakes facilitates and expedites the absorption of the sulfur by the alkali during the subsequent heating of the cakes, such compressing and sub sequent heating constituting one of the essential features of the invention, as above in- '50 dicated. This quickening action may be explained by reference. to the fact that by compressing the mixture the rubber waste is brought into closer contact with the alkali,

so that during. the heating stage the rubber mass is very thoroughly and rapidly acted upon by the alkali, which speedily absorbs the sulfur as the rubber becomes desulfurized and may afterward in the washing-out process be readily removed. In previous processes of this kind the mixture at some stage or other has been liquefied, either by introducing oils or by melting. My process, which involves the use of dry ingredients and the maintaining of a temperature below the melting point220 to 280 'oentigradeis distinctively a dry process from start to finish, with the result that the product is dry, and hence has no objectionable qualities, as undue stickiness, which makes it difiicult to carry out the washing-out process. If there is much filling in the rubber waste, I may incorporate with the aforesaid mixture some dry pulverized resin, such as colophony, before compressin Having thus i illy described my invention, What I claim as new, and desire to-secure by Letters Patent of the United States, is

1. The process of reclaiming vulcanizedrubber waste which consists in disintegrating the waste material, mixing it with an alkali, then compressing the mass, and then heating the mass, substantially as described.

2. The process of reclaimin vulcanizedrubber waste ,which consists in disintegrating the waste material, mixing it with an alkali and with a resin, then compressing the mass, and then heating the mass, substantially as described. i

3. The process of reclaiming vulcanizedrubber waste which consists in disintegrating the waste material, mixing it in a dry state with a dry alkali, and then heating the mass to a temperature of 220 to 280 centigrade, substantially as described.

4. The process of reclaimin vulcanized: rubber waste which consists in isintegrating the waste material, mixing it in a dry state with a dry alkali, and then heating the mass to a temperature of 220 to 280 centigrade for a period of from two to three hours, substantially as described.

ADOLF KITTEL.

Witnesses ALvEsTo S. HoGUE, AUGUST FUGGEn. 

